Saint Marys County Maryland is covered by a total of 30 ZIP Codes. There are 3 ZIP Codes in Saint Marys County that extend into adjacent counties (Charles County, and Westmoreland County). Of the ZIP codes within or partially within Saint Marys County there are 25 Standard ZIP Codes and 5 PO Box ZIP Codes.
Click on the ZIP Codes in the interactive map to view more information. The map control in the upper right corner can be used to toggle map layers on and off. The red outline is the border of Saint Marys County and can be turned on and off. Each type of postal code can also be turned on and off.